Silver can be a potential antimicrobial agent. Silver has been known to possess strong antimicrobial properties. Silver ions such as silver nitrate and sulfadiazine had been used for the treatment of burns, wounds and several bacterial infections. Their use was largely discontinued in the 1940s, due to the development of modern antibiotics and side effects due to the presence of ionic silver.
Silver nanoparticles have unique optical and electrical properties. Colloidal silver is one of the mostly used substrates for Surface Enhanced Raman Spectroscopy (SERS) for single molecule detection. The highly reflective silver nanoparticles have also been used in metal film plasmonic solar cells to improve the conversion efficiency from photos to electrons. The capability of making highly conductive traces and films at low temperatures is of enormous commercial interest to the electronics industry.
Silver nanoparticles can be produced by various processes such as chemical reduction of silver salts in an aqueous and organic solution, radiation assisted—chemical and photoreduction in reverse micelles, thermal decomposition of silver compounds, evaporation and condensation of silver metal, etc.
The chemical reduction methods are based on reduction of silver salt with a number of reducing agents including sodium citrate, sodium borohydride, hydroxylamine hydrochloride, hydrazine, and ethylenediaminetetraacetic acid (EDTA), ascorbic acid, polyol, etc. A stabilizing agent needs to be added to the reaction mixture to prevent the aggregation of the silver nanoparticles formed unless the reducing agent itself is a stabilizing agent (such as citrate).